The thoracodorsal nerve is a motor nerve arising from the posterior cord of the brachial plexus.
It supplies motor innervation to the latissumus dorsi of the upper back.
Course
The thoracodorsal nerve originates from the posterior cord of the brachial plexus in the apex of the axilla.
It typically lies between the upper and lower subscapular nerves, posterior to the subscapular artery.
The nerve descends along the posterior wall of the axilla, before passing anterior to the artery – which now becomes the thoracodorsal artery.
Together, this neurovascular bundle crosses the inferior border of teres major, before piercing the latissumus dorsi muscle.
Fig 1 – The thoracodorsal nerve arises from the posterior cord of the brachial plexus to innervate the latissimus dorsi muscle
Sensory Functions
The thoracodorsal nerve has no sensory function.
Motor Functions
The thoracodorsal nerve supplies motor innervation to the latissimus dorsi muscle.
